In the latest edition of Iwata Asks, Nintendo legend Shigeru Miyamoto revealed that it's easy to make Mario games:
"Looking back, what's been easy about making the Mario games is that they could naturally change along with the progress of technology. For example, when you make live action SFX movies and as special effects technology advances, then you have new methods at your disposal.
"In the same way, as technology advances, the Mario games change, too. On the contrary, books have basically always been made the same way. If it had been necessary to keep making Mario games in the same way like that, we couldn't have done it. In that way, making the Mario games has been easy."
Image Credit: Nintendo